Update query for Mysql

Question

Hello All,
     i need to update few columns from integer to decimal. my database like below
          ________________________
         |  S.No   |   Wattage  |  BBK  | 
         ________________________
         |    1       |    0.236  |   12    |
         ________________________
         |   2        |       23    ||  13     |
         ________________________
   
like above wattage columns  some have decimal value some columns have integer vale. so i need to update through Mysql Query like below 
______________________
| S.No | Wattage | BBK     |
______________________
| 1       |    0.236    |    12    |
______________________
| 2       |    23.000 |     13    |
______________________
 
 Thanks in Advance